Multi-level logic optimization for large scale ASICs

The authors developed an efficient high-level synthesis and optimization system for large-scale circuits, which reduces the total number of fan-ins in the technology-independent phase and adjusts speed and area after technology mapping is completed. A description is presented of multi-level logic optimization techniques based on refined weak division methods and additional functions for carrying out good optimization with only a slight overhead. The authors also describe technology mapping and local optimization techniques suitable for high-level CAD systems. The system has shown that multi-level logic optimization in VLSIs with more than 100,000 gates (that is, VLSIs whose control logic comprises more than 10,000 gate circuits) is possible in practical CPU time.